Tree harvester head with lubrication system for multiple saws

ABSTRACT

A tree harvester head includes first and second saws, each of which comprises a cutting chain, and a lubrication system configured to lubricate the cutting chains of the first and second saws. The lubrication system comprises a source of pressurized lubricant and a diverter valve configured to divert flow of pressurized lubricant, from the source of pressurized lubricant, between the first and second saws for lubrication of the respective cutting chains.

FIELD OF THE DISCLOSURE

The present disclosure relates to a tree harvester head. Moreparticularly, the present disclosure relates to lubrication of thecutting chains of multiple saws of the tree harvester head.

BACKGROUND OF THE DISCLOSURE

Tree harvester heads are typically equipped with a main saw at the baseof the head. The main saw is used for felling trees and cross-cuttingthe trees once they have been felled.

Some tree harvester heads are also equipped with a topping saw. This sawis typically fitted to the upper portion of the head and is used forvalue recovery of the trees.

Each of the saws has a cutting chain disposed about a guide bar of thesaw. Such cutting chains are lubricated to facilitate their operationand prolong their useful life.

SUMMARY OF THE DISCLOSURE

According to the present disclosure, there is provided a tree harvesterhead comprising first and second saws, each of which comprises a cuttingchain, and a lubrication system configured to lubricate the cuttingchains of the first and second saws. The lubrication system comprises asource of pressurized lubricant and a diverter valve configured todivert flow of pressurized lubricant, from the source of pressurizedlubricant, between the first and second saws for lubrication of therespective cutting chains. Such an arrangement is particularly usefulwith a tree harvester head in which the first saw is the main saw of thehead for felling and cross-cutting a tree, and the second saw is atopping saw just for cross-cutting a tree. The diverter valve may beoperated electrically or hydraulically. An associated method ofoperating the tree harvester head is disclosed.

The above and other features will become apparent from the followingdescription and the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description of the drawings refers to the accompanyingfigures in which:

FIG. 1 is a side elevational view showing a forestry machine having atree harvester head attached to a carrier via a boom assembly;

FIG. 2 is a front elevational view showing the tree harvester head in anupright, harvesting position and having a first, main saw near thebottom of the head and a second, topping saw near the top of the head;

FIG. 3 is a perspective view showing the tree harvester head in aprocessing position;

FIG. 4 is a simplified diagrammatic view showing a lubrication systemfor the cutting chains of the two saws of the tree harvester head, andelectronic control of a diverter valve of the lubrication system;

FIG. 5 is a sectional view taken along lines 5-5 of FIG. 3 showing alubricant reservoir mounted to the chassis of the tree harvester head;

FIG. 6A is a simplified diagrammatic view showing hydraulic control ofthe diverter valve along with a saw motor associated with the secondsaw; and

FIG. 6B is a simplified diagrammatic view showing hydraulic control ofthe diverter valve along with a bar cylinder associated with the secondsaw.

DESCRIPTION OF THE DRAWINGS

Referring to FIG. 1, an exemplary forestry machine 10 comprises a treeharvester head 12 attached to a carrier 14 via a boom assembly 16. It isto be understood that the tree harvester head 12 may be used with anysuitable carrier 14 and boom assembly 16.

Referring to FIGS. 2 and 3, the tree harvester head 12 is attachable tothe boom assembly 16 via a hanger 18 for suspension from the boomassembly 16. Illustratively, the hanger 18 comprises a hanging bracket20 to which the head 12 is pivotally attached and a rotator 22 forrotating the hanging bracket 20 and head 12 about an axis 24.

The head 12 is pivotal relative to the hanging bracket 20 between agenerally upright, harvesting position for felling a tree (FIGS. 1 and2) and a generally prone, processing position for processing a felledtree (FIG. 3). In the harvesting position, a number of grippingelements, such as, for example, grapple arms 26 a, 26 b and the drivewheels 28 a, 28 b of drive arms 30 a, 30 b, grip the unfelled tree,after which a main, first saw 32 is activated by the operator to fellthe tree. The head 12 is then pivoted to its processing position so asto hold the felled tree in a generally horizontal position forprocessing, in which the drive wheels 28 a, 28 b, and 28 c drive thefelled tree back and forth as needed along knives 34 a, 34 b, formed onthe grapple arms 26 a, 26 b, and a knife 34 c, formed at an end of thechassis 35 of the head 12, to delimb the felled tree. The first saw 32may then be used to cross-cut the tree into pieces of desired lengthmeasured by use of a length-measuring wheel 36 or other length-measuringdevice.

Exemplarily, the first saw 32 is mounted to the chassis 35 at a basethereof for pivotal movement relative thereto, while a topping, secondsaw 38 is mounted to the chassis 35 at the upper portion thereof forpivotal movement relative thereto. As such, the drive wheels 28 a, 28 b,28 c, drive arms 30 a, 30 b, knives 34 a, 34 b, and length-measuringdevice 36 are positioned between the saws 32, 38. While the first saw 32may be used to cross-cut the tree held by the gripping elements of thehead 12 at the base of the head 12, the second saw 38 may be used tocross-cut the tree at the upper portion of the head 12. It is to beunderstood that the second saw 38 may be mounted to the chassis 35 at avariety of locations other than at the upper portion thereof.

Referring to FIG. 4, each saw 32, 38 is configured as a chain saw so asto have a guide bar 40 and a cutting chain 42 disposed about the guidebar 40 for movement along the periphery thereof upon activation of therespective saw 32, 38. A lubrication system 44 of the head 12 isconfigured to lubricate the cutting chains 42 of the first and secondsaws 32, 38.

The lubrication system 44 comprises a source of pressurized lubricant 46and a diverter valve 48. The diverter valve 48 is configured to divertflow of pressurized lubricant, from the source of pressurized lubricant46, between the first and second saws 32, 38 for lubrication of therespective cutting chains 42.

Exemplarily, the source of pressurized lubricant 46 comprises alubricant reservoir 49, a pump 50, and a pump operator 52 configured tohydraulically operate the pump 50. Lubricant is gravity-fed from thereservoir 49 to the pump 50 configured, for example, as a plunger pumpwith a spring-biased piston mounted in a housing for reciprocatingaction. The pump 50 is positioned fluidly between the reservoir 49 andthe diverter valve 48 and is configured to pump lubricant from thereservoir 49 through the diverter valve 48 to the first saw 32 or thesecond saw 38 as determined by the position of the diverter valve 48.

The pump operator 52 hydraulically operates the pump 50. Exemplarily,the pump operator 52 comprises a pressure-reducing valve 54, whichreduces the pressure of the main supply of hydraulic fluid from thecarrier 14 to a predetermined level (e.g., 90 bars), and a valve 56electronically controlled by a control system 55. The valve 56 controlsthe flow of hydraulic fluid, reduced in pressure by thepressure-reducing valve 54, to the pump 50 in response to a controlsignal from the control system 55 (e.g., 300 ms ON and 400 ms OFF).

The diverter valve 48 is configured to divert flow of lubricant, pumpedfrom the reservoir 49 by the pump 50, between the first and second saws32, 38 for cutting-chain lubrication. The diverter valve 48 iselectronically controlled by the control system 56, and has twopositions: a first position 48 a for diverting flow of lubricant to thefirst saw 32, and a second position 48 b for diverting flow of lubricantto the second saw 38. Exemplarily, since only one saw 32, 38 will beoperating at a time, in the first position, the diverter valve 48 notonly diverts flow of pressurized lubricant to the first saw 32 but alsoblocks flow of pressurized lubricant to the second saw 38, and, in thesecond position, the diverter valve 48 not only diverts flow ofpressurized lubricant to the second saw 38 but also blocks flow ofpressurized lubricant to the first saw 32.

The diverter valve 48 is configured to assume its first position in theabsence of an electronic control signal from the control system 56, andconfigured to assume its second position in response to the controlsignal. The diverter valve 48 is mechanically biased (e.g.,spring-biased) to assume its first position in the absence of thecontrol signal. Upon application of the control signal to the solenoidof the valve 48, the valve 48 shifts to its second position. As such,the diverter valve 48 normally diverts flow of lubricant to the firstsaw 32, which exemplarily is the main saw for felling and cross-cutting,since the first saw 32 will use most of the lubricant, as compared tothe second saw 38, which is exemplarily the topping saw for onlycross-cutting.

Each of the valves 48, 55 is electronically operated by the controlsystem 55. First and second input devices 58, 60, in the form of, forexample, control buttons located at the operator's station of thecarrier 14, are operable by an operator to request activation of thefirst and second saws 32, 38, respectively.

In response to operation of the first input device 58, the controlsystem 55 activates the first saw 32 and the lubrication system 44. Inparticular, the control system 55 outputs an electronic control signalto the operator valve 56 but does not output any control signal to thediverter valve 48. The control signal to the operator valve 56 pulsesthe valve 56 open and closed (e.g., 300 ms ON and 400 ms OFF) so as tohydraulically operate the pump 50, thereby pressurizing lubricant fromthe reservoir 49 (when OFF, the valve 56 directs flow to the case drainof the carrier 14). The control system 55, however, does not output acontrol signal to the diverter valve 48. As such, the diverter valve 48remains in its first position so as to divert flow of lubricant, pumpedfrom the reservoir 49 by the pump 50, to the first saw 32.

In response to operation of the second input device 60, the controlsystem 55 activates the second saw 38 and the lubrication system 44. Inparticular, the control system 55 outputs an electronic control signalto the operator valve 56 and an electronic control signal to thediverter valve 48. The control signal to the operator valve 56 pulsesthe valve 56 open and closed (e.g., 300 ms ON and 400 ms OFF) so as tohydraulically operate the pump 50, thereby pressurizing lubricant fromthe reservoir 49 (when OFF, the valve 56 directs flow to the case drainof the carrier 14). The control signal to the diverter valve 48energizes the solenoid thereof so that the diverter valve 48 assumes itssecond position so as to divert flow of pressurized lubricant to thesecond saw 38.

Exemplarily, the control system 55 comprises a network of electroniccontrollers (e.g., CAN), including, without limitation, a controller 62onboard the carrier 14 and a controller 64 onboard the head 12. In thisexample, the controller 62 is configured to receive a request signalfrom each input device 58, 60, and send a message corresponding to thatrequest to the controller 64. The controller 64 then outputs thecorresponding control signal(s) to the valves 48, 56. Each controller62, 64 has a processor 66 and a memory 68, the memory 68 having storedtherein instructions which, when executed by the processor 66, cause theprocessor 66 to perform the various functions of the controller 62, 64.

Referring to FIG. 5, there is shown a cross-section of the reservoir 49.In this example, the back 70 of the chassis 35 and a pan 72 cooperate toform the reservoir 49. In this way, the reservoir 49 is mounted to thechassis 35. A filler neck 80 (FIG. 3) attached to the reservoir 49 isaccessible from the exterior of the head 12 to supply the reservoir 49with lubricant.

Referring to FIGS. 6A and 6B, the diverter valve 48 may be operatedhydraulically. For example, in FIG. 6A, a control system 155pilot-operates the diverter valve 48 upon activation of a saw motor 90attached to the saw 38. The control system 155 comprises a control valve157 under the control of the controller 64. The control valve 157 is,for example, a proportional valve movable between a first position 157 adepressurizing the pilot port 158 of the diverter valve 48 and the pilotport 91 of a motor valve 92 fluidly coupled to the saw motor 90, and asecond position 157 b pressurizing those pilot ports 158, 91.

In response to operation of the first input device 58, the controlsystem 155 activates the first saw 32 and the lubrication system 44. Inparticular, the control system 55 outputs the electronic control signalto the operator valve 56, so as to operate the valve 56 in theaforementioned manner, pressurizing lubricant from the reservoir 49.However, the control system 155 does not output an electronic controlsignal to the control valve 157 so that the control valve 157 remains inits first position. As such, the pilot ports 158, 91 are depressurizedso that the diverter valve 48 remains in its first position divertingflow of lubricant, pumped from the reservoir 49 by the pump 50, to thefirst saw 32, and the saw motor 90 associated with the saw 38 remainsinactive.

In response to operation of the second input device 60, the controlsystem 155 activates the second saw 38 and the lubrication system 44. Inparticular, the control system 155 outputs an electronic control signalto the operator valve 56, so as to operate the valve 56 in theaforementioned manner, pressurizing lubricant from the reservoir 49, andoutputs an electronic control signal to the control valve 157. Thecontrol signal to the control valve 157 energizes the solenoid thereofso that the control valve 157 assumes its second position. As such, thepilot ports 158, 91 are pressurized so that the diverter valve 48assumes its second position diverting flow of lubricant, pumped from thereservoir 49 by the pump 50, to the second saw 38, and the saw motor 90associated with the saw 38 is activated so as to activate the saw 38.

In FIG. 6B, a control system 255 pilot-operates the diverter valve 48upon actuation of the guide bar 40 of the second saw 38 (i.e., uponpivotal movement of the guide bar 40 for cross-cutting).

The control system 255 comprises a control valve 257 under the controlof the controller 64 for controlling movement of a bar cylinder 94attached to the saw 38 to pivot the saw 38 between storage and cuttingpositions. Exemplarily, retraction of the cylinder 94 moves the saw 38outside its housing to a cutting position, whereas extension of thecylinder 94 moves the saw 38 into its housing to a storage position. Itis to be understood that the cylinder 94 may be plumbed in reverse foropposite movement of the saw 38.

The control valve 257 is configured to assume a first position 257 a inthe absence of an electronic control signal and a second position 257 bupon application of an electronic control signal to its solenoid. In thefirst position 257 a, the valve 257 is configured to direct flow ofhydraulic fluid to a head port 94 a of the bar cylinder 94. In thesecond position 257 b, the valve 257 is configured to direct flow ofhydraulic fluid to a rod port 94 b of the bar cylinder 94. The divertervalve 48 has a pilot port 258 fluidly coupled to the rod port 94 b sothat, in the first position 257 a of the control valve 257, the pilotport 258 is depressurized causing the diverter valve 48 to assume itsfirst position 48 a, and, in the second position of the control valve257, the pilot port 258 is pressurized causing the diverter valve 48 toassume its second position 48 b.

In response to operation of the first input device 58, the controlsystem 255 activates the first saw 32 and the lubrication system 44. Inparticular, the control system 255 outputs an electronic control signalto the operator valve 56, so as to operate the valve 56 in theaforementioned manner, pressurizing lubricant from the reservoir 49.However, the control system 255 does not output an electronic controlsignal to the control valve 257 so that the control valve 257 remains inits first position. As such, the pilot port 258 of the diverter valve 48is depressurized so that the diverter valve 48 remains in its firstposition diverting flow of lubricant, pumped from the reservoir 49 bythe pump 50, to the first saw 32.

In response to operation of the second input device 60, the controlsystem 255 activates the second saw 38 and the lubrication system 44. Inparticular, the control system 255 outputs an electronic control signalto the operator valve 56, so as to operate the valve 56 in theaforementioned manner, pressurizing lubricant from the reservoir 49, andoutputs an electronic control signal to the control valve 257. Thecontrol signal to the control valve 257 energizes the solenoid thereofso that the control valve 257 assumes its second position. As such, thepilot port 258 of the diverter valve 48 is pressurized so that thediverter valve 48 assumes its second position diverting flow oflubricant, pumped from the reservoir 49 by the pump 50, to the secondsaw 38.

Referring back to FIG. 3, the valves 48, 55 may be included in a valvebank 82 of the head 12, as shown, for example, with respect to valve 48.Exemplarily, the valve bank 82 is mounted to the chassis 35, such as tothe chassis back 70, and covered by a valve cover 73. It is to beunderstood that either or both of valves 48, 55 may be mounted to thechassis 35 separate from the main valve bank 82.

The lubrication system 44 has a number of benefits. For example, becauseof the diverter valve 48, it is able to employ a single source ofpressurized lubricant for both saws 32, 38. As such, it has a singlereservoir 49 and a single pump 50, in common with both saws 32, 38,promoting design and space efficiency.

Further, the lubrication system 44 employs a single type of lubricant.This lubricant is, for example, a lubricant, without hydraulic oil, thatis more environmentally friendly than hydraulic oil and promotes theuseful life of the cutting chains 42 and guide bars 40 more so thanhydraulic oil. The lubricant may be a biodegradable chain lubricationoil, such as, for example, BP Bioforst 2000.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such illustration and description isto be considered as exemplary and not restrictive in character, it beingunderstood that illustrative embodiments have been shown and describedand that all changes and modifications that come within the spirit ofthe disclosure are desired to be protected. It will be noted thatalternative embodiments of the present disclosure may not include all ofthe features described yet still benefit from at least some of theadvantages of such features. Those of ordinary skill in the art mayreadily devise their own implementations that incorporate one or more ofthe features of the present disclosure and fall within the spirit andscope of the present invention as defined by the appended claims.

The invention claimed is:
 1. A tree harvester head, comprising: firstand second saws, each of which comprises a cutting chain, and alubrication system configured to lubricate the cutting chains of thefirst and second saws, the lubrication system comprising: a source ofpressurized lubricant; and a diverter valve that comprises an inlet portfluidly coupled to the source of pressurized lubricant, a first outletport fluidly coupled to the first saw, and a second outlet port fluidlycoupled to the second saw, the diverter valve configured to divert flowof pressurized lubricant, from the source of pressurized lubricant,between the first and second outlet ports and thus the first and secondsaws for lubrication of the respective cutting chains, the divertervalve configured to assume a first position for diverting flow ofpressurized lubricant to the first saw in the absence of a controlsignal, and a second position for diverting flow of pressurizedlubricant to the second saw in response to the control signal, whereinthe tree harvester head is included in a forestry machine comprising afirst input device operable to request activation of the first saw, asecond input device operable to request activation of the second saw,and a control system that controls the diverter valve and is configuredto output the control signal to the diverter valve in response tooperation of the second input device but not in response to operation ofthe first input device.
 2. The tree harvester head of claim 1, whereinthe first saw is configured to fell and cross-cut a tree, and the secondsaw is configured to cross-cut a felled tree held by the tree harvesterhead.
 3. The tree harvester head of claim 1, wherein the source ofpressurized lubricant comprises a lubricant reservoir, a pump positionedfluidly between the lubricant reservoir and the diverter valve, and apump operator configured to operate the pump, and the control system isconfigured to output a control signal to the pump operator commandingoperation of the pump in response to operation of each of the firstinput device and the second input device.
 4. The tree harvester head ofclaim 1, comprising an electronic controller electrically coupled to thediverter valve.
 5. The tree harvester head of claim 3, furthercomprising: a saw motor attached to the second saw, a motor valvefluidly coupled to the saw motor, a control valve, and an electroniccontroller electrically coupled to the control valve, the diverter valvecomprises a pilot port, the motor valve comprises a pilot port, and thecontrol valve is fluidly coupled to the pilot port of the diverter valveand the pilot port of the motor valve.
 6. A tree harvester head,comprising: first and second saws, each of which comprises a cuttingchain, a lubrication system configured to lubricate the cutting chainsof the first and second saws, the lubrication system comprising a sourceof pressurized lubricant and a diverter valve that comprises an inletport fluidly coupled to the source of pressurized lubricant, a firstoutlet port fluidly coupled to the first saw, and a second outlet portfluidly coupled to the second saw and is configured to divert flow ofpressurized lubricant, from the source of pressurized lubricant, betweenthe first and second outlet ports and thus the first and second saws forlubrication of the respective cutting chains, wherein the diverter valveis configured to assume a first position for diverting flow ofpressurized lubricant to the first saw in the absence of a controlsignal, and a second position for diverting flow of pressurizedlubricant to the second saw in response to the control signal, a barcylinder attached to a guide bar of the second saw, a control valvefluidly coupled to the bar cylinder and a pilot port of the divertervalve, and an electronic controller electrically coupled to the controlvalve.
 7. The tree harvester head of claim 6, wherein the source ofpressurized fluid comprises a lubricant reservoir and a pump positionedfluidly between the lubricant reservoir and the diverter valve.
 8. Thetree harvester head of claim 6, wherein the source of pressurizedlubricant comprises a biodegradable lubricant, without hydraulic oil,for both saws.
 9. A method of operating a tree harvester head, the treeharvester head comprising first and second saws, each of which comprisesa cutting chain, and a diverter valve comprising a first outlet portassociated with the first saw and a second outlet port associated withthe second saw, the method comprising: diverting flow of pressurizedlubricant, from a source of pressurized lubricant of the tree harvesterhead, between the first and second outlet ports and thus the first andsecond saws for lubrication of the respective cutting chains, whereinthe diverting comprises diverting flow of pressurized lubricant with thediverter valve by moving the diverter valve between a first position fordiverting flow of pressurized lubricant to the first saw and a secondposition for diverting flow of pressurized lubricant to the second saw,the diverting comprises controlling the diverter valve such that thediverter valve assumes the first position in the absence of a controlsignal and assumes the second position in response to the controlsignal, the controlling comprises a control system outputting thecontrol signal in response to operation of a second input deviceassociated with the second saw but not in response to operation of afirst input device associated with the first saw.
 10. The method ofclaim 9, wherein the diverting comprises the control system outputting acontrol signal commanding operation of a pump, positioned fluidlybetween a lubricant reservoir and the diverter valve, in response tooperation of each of the first input device and the second input device.11. The method of claim 9, wherein the diverting compriseselectronically operating the diverter valve.
 12. The method of claim 9,wherein the diverting comprises hydraulically pilot-operating thediverter valve.
 13. The tree harvester head of claim 1, wherein thefirst position is configured for diverting flow of pressurized lubricantfrom the first outlet port to the first saw and blocking flow ofpressurized lubricant from the second outlet port to the second saw andthe second position is configured for diverting flow of pressurizedlubricant from the second outlet port to the second saw and blockingflow of pressurized lubricant from the first outlet port to the firstsaw.